OPNAVINST 5442.2 for specific identificationof reporting custodians.)REPORTING PERIODFor the purpose ofthe MDS, a reporting period is 1 month.SERVICE LIFEThe time period duringwhich the item can be maintained in servicewithout replacement. Each program aircraft,from acceptance to strike, follows a life cycleconsisting of alternate periods of operating andrework time as prescribed for each model byOPNAVINST 3110.11. Aircraft become eligiblefor strike upon completion of the life cyclespecified for the model by the latest edition ofOPNAVINST 3110.11.SERVICE PERIODA prescribed segmentof the service life of aircraft subject to the SDLMprocess; for example, a stated number of calendarmonths or accumulated flight hours that anaircraft is in the physical custody of an operatingactivity for use prior to SDLM or retirement. Thenumber and length of the standard serviceperiods, together with associated planning factorsand policies, are set forth in the latest edition ofOPNAVINST 3110.11. Certain principles are setforth below:1. It is intended that aircraft undergoingSDLM and SDLM/modification remain in thecustody of the operating unit unless transfer isdictated by operational commitments. Aircraftundergoing SDLM/crash damage or SDLM/conversion are transferred to NAVAIR fleetsupport custody during rework and are notnecessarily returned to the previous operatingcommand upon completion.2. The number of the service period is anumber that will approximately locate the currentposition of an aircraft in its prescribed standardservice life. Accumulated operational servicemonths on the aircraft more precisely locate itsposition in service life.3. The responsibility for the determinationand logbook entry of the number of the serviceperiod for an aircraft in the controlling or physicalcustody of a NAVAIR fleet support activity restson the NAVAIR custodian having physicalcustody of the aircraft. Reporting custodians ofaircraft are governed by the aircraft logbookentries made by the NAVAIR fleet supportactivity custodians with respect to service periodand accumulated operational service months.4. The number of the service period foraircraft in the controlling and reporting custodyof a NAVAIR fleet support activity is normallyone less than the number of the service period theaircraft will be in (as determined by the NAVAIRfleet support activity) if and when next transferredto an operating command.5. Aircraft transferred directly from oneoperating activity to another continue withthe same service period number. Accumulatedoperational service and flying hours in serviceperiod will be carried over.6. An aircraft reaches the end of its serviceperiod by accumulating the prescribed number ofcalendar months or flying hours. At this time theaircraft is due for return either to NAVAIR fleetsupport physical custody for SDLM or toNAVAIR fleet support controlling custody forretirement. (See the latest edit ion of OPNAVINST5442.2.)STANDARD NAVY DISTRIBUTION LIST(SNDL)A list providing official addressing anddistribution information for the Naval Establish-ment. Published in two parts: Part 1, theOperating Forces of the Navy, OPNAVINSTP09B2-107, and Part 2, Catalog of Naval ShoreActivities, OPNAV P09B2-105. (See the latestedition of SECNAVINST 5215.1.)SUPPORT EQUIPMENT (SE)All equip-ment required on the ground to make anaeronautical system, command and controlsystem, support system, subsystem, or end itemof equipment operational in its intendedenvironment. This includes all equipment requiredto launch, arrest (except Navy shipboard andshore-based launching and arresting equipment),guide, control direct, inspect, test, adjust,calibrate, gauge, measure, assemble, disassemble,handle, transport, safeguard, store, actuate,service, repair, overhaul, maintain, or operate thesystem, subsystem, and item or component. Thisdefinition applies regardless of the method ofdevelopment, funding, or procurement. SE maybe categorized as common (general-purpose) andpeculiar (special-purpose).TECHNICAL DIRECTIVE (TD)A docu-ment authorized and issued by NAVAIR. Itprovides technical information necessary toproperly and systematically inspect or alter theconfiguration of aircraft, engines, systems, orequipments subsequent to establishment of eachrespective baseline configuration. These technicalAI-12